The influence of platinum on the oxidation and sodium sulfate induced hot corrosion of NiAl diffusion coatings
Journal article, 2011
Oxidation and corrosion properties at 900 degrees C of two coatings, one containing platinum and the other platinum-free, on IN792 were investigated. During the corrosion exposures, sodium sulfate salt was situated in the furnace together with the coated specimens. The temperature of the salt was kept above its melting point but lower than the temperature of the coating i.e. 900 degrees C. The exposure times ranged from 100 to 1000 h. The formed oxide scales were studied by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy and scanning transmission electron microscopy techniques. It is shown that the presence of Pt improves the protective properties of the coating against corrosion. The propagation stage of corrosion on the platinum-free coating is reached already after 100 h of exposure. On the other hand the scale formed on the platinum-rich samples still appeared to be protective even after 500 h. The details concerning structure and chemistry of the scales formed are presented and discussed.
surface & coatings technology
tlock gj
growth
diffusion coatings
superalloy
1990
wancy hm
v41
oxide scale
p1
p710
sodium sulfate corrosion
adhesion
2011
1991
werkstoffe und korrosion-materials and corrosion
microstructure
alloys
modified aluminide coatings
p1
resistance
odeshmukh v
behavior
influence of platinum
v49
oxid met
Author
Haiping Lai
Chalmers, Applied Physics, Microscopy and Microanalysis
Pavleta Knutsson
Chalmers, Applied Physics, Microscopy and Microanalysis
Krystyna Marta Stiller
Chalmers, Applied Physics, Microscopy and Microanalysis
Materials at High Temperatures
0960-3409 (ISSN)
Vol. 28 4 302-308Subject Categories
Materials Engineering
DOI
10.3184/096034011X13188762374132